Synthesis And Visible-Light Photocatlysis Performance Research Of BiVO₄ Heterostructure Photocatalysts

For construction of a resource-conserving, environment-friendly society and resolving the two big crises of energy and environment, the development of new solar photocatalytic technology has become an increasingly larger research subject of scientists. From this aspect, this article studied new nanoheterostructure solar photocatalytical materials and put forward some feasible experiment schemes and research methods, then combining theories and experiments, the photocatalytical chemical reactions'influence factors and the related mechanisms were stated in detail.Because bismuth vanadate not only has bright color, but also has a series of important properties: ferroelasticity, thermochromism, acoustooptic effect, ionic conductivity, semiconductor properties, etc. and in respect of sensors, fuel cells, high performance pigments, etc., it has extensive and important application prospect. In this article, the preparation of BiVO₄ was used hydrothermal method whose conditions are relatively mild and micromorphology is controllable, then the BiVO₄ particles would be nanoparticles. In the prepared process, the factors of temperature, time, acidity and alkalinity, etc. were studied on surface morphology and performance of the samples, then the sample in optimization process conditions was characterized by X-ray Diffraction, Scanning Electron Microscope, UV-vis diffuse reflection and photocatalytic performance analysis, and then based on the surface microstructure transmutation of the sample, the possible formantion mechanism was put forward and explained. In addition, this article also discussed the impact of different surfactants or templates on the morphology of sample and proposed relevant mechanism explanations.Photocatalysts with heterostructure have series features that are different from single homogeneous photocatalysts such as easier to accept photons irradiation, stronger ability for electronic excitation, better electronic or ion conductivity, more effective for electron-hole pair separation. Nanoheterostructures, which integrate the advantages of nanotechnology, semiconductor technolgy and heterosturctures'configuration, have been more widespread used in the preparation of chemical materials and performance research of materials. The semiconductor cadmium sulphide has narrower bandgap, higher conduction band level and forms heterostructure composites with bismuth vanadate easily, so this paper will choose to compound the bismuth vanadate and cadmium sulphide, prepare heterostructure photocatalysts by second hydrothermal method and give samples'morphology characterization and performance analysises. Meanwhile, photocatalytic reaction mechanism and electron-hole pair's separation process are discussed. Furthermore, BiVO₄-M_xO_y (M=Fe,Ti,Bi) composites photocatalysts were studied.